单项选择题

The dog has been of most value to man m the development of（）

A．a treatment for rabies
B．open-heart surgery
C．a cure for distemper
D．all of the above

<上一题 目录 下一题>
热门 试题

单项选择题
In the polar regions, the dog mainly （）

A．carried supplies
B．provided companionship
C．tracked prey
D．herded caribou(驯鹿)
单项选择题
30（）

A．Long ago
B．Not long ago
C．More recently
D．Later
相关试题